Complying with city conflicts rules could cost Mayor Bloomberg millions, but the billionaire mayor said yesterday he’s unconcerned because “there are other things in life than playing with your stock portfolio.”

“Get a life, will you? Get back to work,” the mayor chided a reporter who asked about a Conflicts of Interest Board decision last week requiring that Bloomberg dispose of his vast stock holdings within 90 days.

“I’ve got a city to run here. I’m not doing it to manage my portfolio.”

The ruling – which Bloomberg sought before he took office – could be costly, since stocks are in the tank and the mayor likely would have to sell at distress-level prices.

The mayor has said he’s going to transfer a lot of money from stocks into mutual funds, which the conflicts board approves because they represent baskets of stocks over which individual shareholders have little influence.

Bloomberg – who has to sell at least $45 million in stock holdings – admitted he was “a little surprised” that the conflicts board also barred him from trading municipal bonds.

“So I agreed I would invest in the future of New York City and buy municipal bonds and I will hold them to maturity. I didn’t plan to sell them anyway,” said the mayor.

Bloomberg could get a hefty tax write-off from the stock market losses to offset his presumed nine-figure income.

Bloomberg won’t say how much he’s worth – but last year he gave more than $100 million to charity.

Though he’ll have to sell his stocks, Bloomberg will remain the owner of Bloomberg LP, his financial information and media company. Bloomberg said he expects to be consulted before the company makes any major decisions.

The Conflicts of Interest Board is still examining some other high-level administration officials with considerable assets – including Deputy Mayor Dan Doctoroff, who works for $1 a year.